June 2007

4500 mm CPP coextrusion line in test run

The new Polycast® line installed at B-Pack Due® keeps the premises about the performances we previously announced (see newsletter no.2). The line, with its 4500 mm of useful width, is the second one of big dimensions installed at the company in Tuscany. The first line, always of the same width, entered in exercise in 2004 and up today the production capacity of B-Pack Due® is close to 30.000 t/year. The manufacturing of PP cast film with high performing lines allows a conspicuous reduction of the costs per kg of the produced material. This reduction is well accepted in the fields with higher additional value, such as the food, medical and pharmaceutical fields, but it is even essential to propose a competitive price in the overstocked fields such as textile, flowers, lamination and BOPP, etc. The PP cast film is rapidly getting affirmed on the market thanks to its marking characteristics and in many cases it replaced PE or PVC film. In fact if PP is correctly extruded, it allows higher brilliancy and glossiness values in addition to a higher mechanical resistance as well as warmth resistance. The best choice is producing mother reels with full width and in a second time to cut them with a slitting machine. The in-line cutting is really unadvisable for high speeds, as PP cast film tends to shrink and its polymers also after extrusion. Consequently a reel with a good aspect, immediately after the extrusion, not necessarily will keep it after some days. Only with some film structures you can effect the in-line cutting, even considering the speed limitation. We get back to the new Polycast® line. It is equipped with an even more performing technology than the previous line, allowing in this way to get high productions and operation speed up to 350 m/min. Such values do not compromise the film’s quality , which keeps on corresponding to the application necessities of the market. The extrusion zone is made up by 4 high capacity extruders, two with 180 mm diam. and two with 130 mm diam., with a trimmed edges recovery system with forced hopper. Such a configuration allows exceptional values of gross output (3.000 kg/h) and additionally it is useful in order to optimize some multilayer structures, among which, for example, those for the production of twist film. The die with Ids of 5.500 mm and the 5 layers feedblock by Cloeren grant a very good stratification of the material and a high pressure resistance during high speed production. The thickness control is effected by Electronic Systems double scanner with reading system and tolerances’ correction, while mero is the choice for the Corona treatment. The Refesave® trimmed edges recovery system, developed by Colines®, works on 2 different cutting stations and allows the recovery of the side trimmed edges without regranulation, and so without risks as regards the films’ quality, and an homogeneous corona treatment on the full film width. In the final part of the line is placed the Jumbowind® winder which, in this last version, allows the winding of mother reels 4500 mm wide, with max. diam. 1200 mm and 4 t weight each. On this line special products for the medical market are already in production. Colines® enhances its own position as reliable technological partner. See also our dedicated website www.polycast.it